A Framingham town employee crashed his car into a utility pole after he told his young niece and nephew who were passengers in the car to "buckle up" because they were "going on a death run," prosecutors said Wednesday.

Peter Curtis, 33, of Medway, was driving on Pleasant Street on Monday night with two children, ages 10 and 15, in his car when he slammed into the pole. Prosecutors said the car was going about 100 mph at the time.

Curtis was charged with two counts of assault with intent to kill, negligent operation of a motor vehicle and two counts of reckless endangerment.

Prosecutors said Curtis had picked up the children at his sister's home. Officials allege Curtis told the children, "You better buckle up because we are going on a death run," before he crashed the car.

Curtis' attorney said the crash was an accident.

"It was a mistake. That's what it was," Curtis said as he left court.

The children were taken to MetroWest Medical Center, and one was later transferred to Tufts Medical Center and was listed in critical condition.